Vibration generator for yarns

ABSTRACT

A vibration generator for yarns in which the yarn is received in a slot in the periphery of a rotating hollow body, the yarn bearing against the body only at the two points at which it intersects the circular outer surface as a secant of that circular surface. The vibration-generating body is pneumatically driven and may include guide grooves to feed the yarn into the vibrating slots.

United States Patent 1191 Sartori 14 1 Sept. 2, 1975 [73] Assignee: Ateliers Roannais de Constructions Textiles, Roanne, France 22 Filed: Sept. 10,1973

21 App1.N0.: 395,600

[30] Foreign Application Priority Data Oct. 3, 1973 France 73.17028 [52] US. Cl. 242/43; 242/181, 242/432 [51] Int. Cl. B6511 54/28 [5 8] Field of Search 242/432, 27, 31, 18.1, 242/43 [56] 1 References Cited UNITED STATES PATENTS 1,727,884 9/1929 lessen 242/432 2,151,327 3/1939 Moncrieff et a1. 242/432 2,249,147 7/1941 Kuppers 242/432 2,550,086 4/1951 Rouge 242/432 2,739,761 3/1956 Haefeli 242/432 Cunningham 242/432 3,235,191 2/1966 Engelman et a1. 242/181 3,241,779 3/1966 Bray ct a1. 242/181 3,523,652 8/1970 S1ijk0ord.... 242/432 3,640,478 2/1972 Starke 242/432 X FOREIGN PATENTS OR APPLICATIONS 426,380 3/1926 Germany 242/432 874,651 8/1961 United Kingdom 242/432 Primary ExaminerStanley N. Gilreath Attorney, Agent, or FirmS h.'erman & Shalloway [5 7 ABSTRACT A vibration generator for yarns in which the yarn is received in a slot in the periphery of arotating hollow body, the yarn bearing against the body only at the two points at which it intersects the circular outer surface as a secant of that circular surface.

The vibration-generating body is pneumatically driven and may include guide grooves to feed the yarn into the vibrating slots.

9 Claims, 9 Drawing Figures PATENTEU 21975 BBDZSYS SHEET 1 BF 3 PATENTEUSEP 21975 7-1. 902676 SHEET 2 BF 3 PATENTEU 21975 sum 3 0f 3 FIGB FHLG

FIG.9

VIBRATION GENERATOR FOR YARNS BACKGROUND OF THE INVENTION The present invention relates to guides for travelling textile yarns and is concerned more particularly with vibration generators for yarns such as in bobbinwinding systems.

BRIEF DESCRIPTION OF THE PRIOR ART A variety of attempts have been made in improving the cohesion of coiled yarns and the adhesion of such yarns to supports such as bobbins.

These have included the use of high winding angles or crossing angles which, however, cannot be used in contemporary high-speed winding operations. One of the limitations here is the extreme linear speeds required of the reciprocating yarn guicle. Yarn-guide speeds in excess of 6 metres per second are encountered, with resultant extreme stresses at the directionreversing points.

Additionally, when synthetic yarns are wound at high angles, they have a tendency to shrink, thereby creating considerable constrictive forces on themselves and on their support. Such pressure can have an effect on the molecular orientation of the yarn and a consequent effect on its physical properties and its overall quality.

Certain attempts have been made at winding yarns in non-uniform turns, such as for example, French Pat. No. 705,253 and US. Pat. No. 1,985,603. These wavy turns are substantially parallel to their adjacent turns within the same layer, but are displaced or disoriented with regard to the turns in adjacent layers. This has increased the average crossing angle between adjacent layers without an increase in the basic winding angle governed by the reciprocating speed of the yarn guide. This improves the stability of the windings, especially at the edges of the wind. Therefore, the stability of a winding may be improved, with a given reciprocating speed of the yarn-guide, or the yam-guide speed may be reduced while maintaining winding-stabilities comparable to the previous results.

More recently, French Pat. No. 1,579,444 employed an oscillating wire actuated by a small, eccentric wheel. However, this apparatus has been found to be too delicate for high-speed winding operations such as those operating above a thousand metres per minute.

Also, complex mechanisms which modify the motion of the bobbin or winding support have been tried but have proven unsuitable for use with heavy bobbins and in high speed operations.

French Pat. No. 1,012,078 discloses a system for vibrating yarns in a direction parallel to the axis of the bobbin on which they are to be wound and using, for example, a diapason or a vibrating blade. This system is an improvement, but it still is not satisfactory for the extreme winding speeds currently being employed.

US. Pat. No. 2,147,664 teaches the vibration of yarns by a rotating cam having a peripheral groove, the cam being traversed over the length of the winding area on the bobbin.

This system was improved upon in French Pat. No. 1,291,807 which employs a hydraulically driven, rotating cam with a peripheral groove to engage and drive the yarn. This system is effective and is particularly suitable for use with glass filaments. However, with other, synthetic fibers, several disadvantages are encountered.

In particular, since the yarn bears against and rubs against the groove in a line-contact against the walls of the groove, it is subjected to significant variations in tension which are most detrimental to inelastic yarns, especially at high winding speeds.

In addition, with a positive rotational drive of the cam, the yarn sometimes winds on the cam itself and can continue to do so until something is broken. Where the mechanical structure is strong enough to take this abnormal load, the hydraulic system is then subjected to extreme loads and pressures, sometimes to the point of rupture of the hydraulic system.

Such ruptures of the hydraulic system causes soilage of the yarns, over and above the soilage which is caused by the inherent leaks always found in the heavy and costly hydraulic drive systems.

Therefore, the prior systems have not been found to be entirely satisfactory in all circumstances.

SUMMARY OF THE INVENTION In general, the preferred form of yarn-vibration generator of the present invention comprises a rotating hollow body or drum having a wavy slot in its cylindrical periphery, the side walls of the slot being smoothed to engage a yarn at two points of intersection of the yarn with the cylindrical surface of the drum. The yarn forms a secant of the circular periphery of the drum and is substantially free of engagement with the drum except for the side walls of the slot which it engages at its points of intersection with the circular periphery.

The drum is driven by an inertia-type, pneumatic drive which is capable of stalling under excessive load.

OBJECTS OF THE INVENTION Therefore, it is an object of the invention to provide a yarn-vibration generator which is effective and reliable at extreme yarn speeds.

It is a further object of the present invention to provide a yarn-vibration generator which applies a lowamplitude reciprocating motion to yarns travelling at extreme speeds.

It is a further object of the invention to provide a yarn-virbation generator which incorporates a minimum area of contact with the yarn.

A still further object of the invention is the provision of a yarn-vibration generator which engages the yarn at two points spaced along the yarn and permits the yarn to remain free and straight between those points.

An additional object of the invention is the provision of a yarn-vibration generator which is capable of stalling under extreme load to prevent damage to the yarn and to the attendant equipment.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects of the present invention will be more fully understood from the following description and the accompanying drawings, in which:

FIG. 1 is a perspective view of a yarn-winding installation incorporating the preferred vibration generator of the present invention;

FIG. 2 is an enlarged side view of the yarn generator of FIG. 1;

FIG. 3 is a sectional view of a portion of FIG. 2; FIG. 4 is a sectional view of the installation of FIG.

FIG. is a view semilar to FIG. 3 and showing a modified form of vibration generator;

FIG. 6 is a perspective view of a modified form of drum;

FIG. 7 is a side view of the drum of FIG. 6; FIG. 8 is a perspective view of a further modified form of drum, and

FIG. 9 is a side view of the drum of FIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIGS. 1 through 4, the preferred form of yarn-vibration generator of the present invention is incorporated in a yarn-winding station in which a textile yarn l is wound on a support or bobbin 2 under guidance of a reciprocating yarn guide 3 which is controlled by a cam 4. The yarn guide 3 is mounted for reciprocation on guide rods 5 and 6 and includes yarndirecting forks 7 and 8 and is otherwise conventional in construction.

However, the fork 7 is formed on part of a housing 9 which carries a hollow rotor or drum 10 therein. The drum 10 is mounted on a core 11. The drum preferably is driven by a compressed air drive, not shown in detail in these FIGS. 1-4, for reasons of clarity, but discussed more fully hereinafter with respect to FIG. 5.

As best shown in FIGS. 2 and 3, the hollow drum 10 has a wave-form slot 12 therein which, since the interior is hollow, receives the yarn in engagement only with the sidewalls l3 and 14 of the outer portion of the drum.

The housing 9 includes a pair of smooth, abrasionresistant guide bars 15 and 16. The guide bar 15 is looped back to form an outside bar 1541. The guide bars, preferably have polished, smooth surfaces and prevent the yarn from hitting sharp areas of the housing and, in the case of the bar 15a, prevent complete escape of the yarn from the guide and vibration generating system.

Preferably, an amount of deflection of the yarn is imposed by protrusion of the fork 7 beyond a straight line from the guide 8 to the bar 15. This slight deflection A serves to dampen the generated vibrations to prevent their travel back to the upstream run of the yarn or to the unwinding point thereof.

As best shown in FIG. 4, the yarn 1 forms a secant with the exterior surface of the drum 10, the two points of intersection being identified by the numerals l7 and 18. Preferably, the angle B between the points 17 and 18 (with respect to lines drawn therethrough to the axis of the drum) is about 70. The distance between the points 17 and 18 may be as required to form the desired angle B, and may or may not bear a relation to the wave pattern of the slot.

The wave form of the slot 12 may take various forms, either a single wave per revolution or multiple waves per revolution. However, in the case of a slot having multiple waves or alternating high points, it is even more advantageous to have the waves of non-uniform length, thereby creating interference and greater action and jumbling of the vibrational waves in the yarn.

However, the frequency of vibration of the yarn, as may be determined by the amplitude and speed of the generator slot 12, preferably is not a whole number of sub-multiple of the circumference of the bobbin being wound.

As shown in FIG. 5, the drum 10 is driven by compressed air entering through the hollow axle 20 which carries it nozzle chamber 21 having a nozzle 22 directed toward a turbine-blade area 23 on the drum. Air entering the drum through the blade area 23 is free to escape through vents 24 on the opposite wall.

The drum 10 is mounted on the axle 20 by means of suitable bearings 25 and 26 which engage the core 11 of the drum.

Air is supplied to the hollow axle 20 by means of a flexible tubing 27 which is free to move with the guide assembly, and which is itself guided such as by opposed U-channels 28 and 29, shown in broken lines in FIG. 1.

Therefore, as the drum 10 is rotated by the effect of the compressed air on the blade area 23, the transverse relationship of the slot sidewalls l3 and 14 produce a transverse displacement of the yarn at the two points 17 and 18, with the internal portion of the yarn being relatively free within the open hollow of the drum 10.

In the case where the slot includes n waves, n being an integer greater than 1, the secant yarn forms a chord which subtends an are or peripheral length of 21r/n between the two points at which the yarn intersects the periphery of the drum. In practice, the waves have the same amplitude and the same frequency. In this case, n is advantageously, at least three, 'and preferably is four, with the secant arcs then being 120 and angle degrees respectively. This arrangement makes it easier for the yarn to enter and be held in the generator, because the yarn is guided therein only at two points which are aligned in a plane perpendicular to the axis of the generator, and thus always parallel to it.

As shown, the median plane of the slot 12 is aligned with and parallel to the motion of the yarn. If desired, the median plane of the slot may be slightly skewed, with respect to the direction of yarn travel, to provide a varied agitation of the yarn and agitation of the free portion thereof between the points 17 and 18.

Other means may be employed, advantageously, to create variations in the vibrations imparted to the yarns. In one form, a multi-wave slot includes wave forms of successively decreasing lengths, the sum of which preferably at least equal to the length of yarn which equals the circumference of the largest-diameter winding to be produced.

Also, the speed of rotation of the drum may be varied. Preferably, this is accomplished by varying the delivery of compressed air to the turbine 23, either uniformly or randomly.

In this respect, we prefer to cycle the rotational speed of the drum between suitable minimum and maximum speeds to yield a suitable average, but non-uniform speed.

Further, it is possible to keep constant the number of waves of yarn, per revolution of the bobbin, regardless of the increasing diameter of the bobbin. The speed or average speed of the drumis gradually reduced as the wound diameter of the bobbin increases. Excellent results are obtained by shifting the drum speed and thus the point of coincidence of the origins of the waves on the bobbin by a value which varies between 0.15 and 0.75, and preferably between 0.25 and 0.50 times the length of the vibration wave.

As shown in FIGS. l-4, the winding station includes a rotating cylinder or pilot roller 30 which drives the bobbin 2 by peripheral contact. Where such pilot rollers are employed with the generators of the present invention, it is desirable to have the generator drum as close as possible to avoid attenuation or loss of the vibrations in the yarn. Especially, the arcuate contact of the yarn with the pilot roller, from its first contact at T to its first contact with the bobbin and winding, should be limited. Quite satisfactory results are obtained at extreme speeds (3,000 meters per minute, or more) when the angle C defining this arcuate contact is within the limits of zero to 30.

As shown in FIGS. 6 and 7, the modified form of wave generating drum 10' includes a chamfered portion 31 having a spiral feed groove 32 which begins shallow adjacent the shoulder of the chamfer 31 and deepens around to intersect the slot 12'. Preferably, the intersection of the groove 32 and the slot 12 is formed at or adjacent an extremity or lateral crest of the slot, while the depth of the groove at that point is sufficient to trap a yarn therein to enter the slot 12'.

Therefore, it is apparent that the drum of FIGS. 6 and 7 is self-feeding, with the groove 32 progressively feeding yarn toward and into the vibration slot 12'.

As shown in FIGS. 8 and 9, another advantageous form of drum 10 includes a recapturing groove 33 which extends along the outer surface of the drum and intersects the slot 12" at point 35. Preferably, the recapturing groove 33 extends across the median plane of the slot 12. The recapturing groove 33 is operable to engage an escaped yarn and reintroduce the yarn into the slot 12".

EXAMPLE A yarn-vibration generator drum was constructed incorporating the several features of the invention, including the feed groove 32 and the recapturing groove 33.

The drum was cut from aluminum stock to form a hollow 16 mm drum having a 7 mm chamfer. The wave slot was cut through the outer surface, with a width of about 1 mm, and included four waves about the circumference of the drum.

A spiral feed groove was cut into the chamber and the outer surface of the drum, the average depth of the deepening groove being approximately l mm. At the point of intersection with the slot 12, however, the groove 32 reaches full depth of the wall carrying the groove, so that the yarn engaged by the groove is then engaged by the walls of the slot 12.

The recapturing groove 33 was made approximately 1 mm wide and 1 mm deep, in accordance with FIGS. 8 and 9.

It is to be understood that the vibration generating drums of the present invention may be formed of any suitable material including metals and plastics, whether they be machined or moulded. The dimensions are not critical in themselves, but it is important that sharp edges or comers are to be avoided.

Where desired, in order to provide both snag-free and abrasion-resistant surfaces, the drums may be coated with a ceramic.

From the foregoing, it is apparent that the present invention provides a uniquely advantageous yarnvibration generator which, where employed in a bobbin winding station, not only improves the stability of the general windings, but even produces a stability of the windings at the end-sections at which the yam-guide mechanism reverses direction, which has been a distinct problem.

Various changes may be made in the details of the invention, as disclosed, without sacrificing the advantages thereof or departing from the scope of the appended claims.

What is claimed is:

l. Apparatus for winding textile yarn including a yarn guide, means for reciprocating said yarn guide, said yarn guide including a vibration generator mounted on said yarn guide for reciprocation therewith, said vibration generator including an assembly comprising a. a hollow drum having a circumferential slot therein, said slot having at least one wave therein,

the interior of said drum being free of obstructions to a yarn entered as a secan't in said slot, and b. air turbine means for rotating said hollow drum at high speed to impart low-amplitude vibrations to the yarn entered in said slot, said air turbine means including an air turbine formed at least in part by said hollow drum.

2. The apparatus of claim 1 in which the slot includes a plurality of waves of the same dimensions.

3. The apparatus of claim 1 in which the hollow drum includes a hub and two outer portions, the outer portions being spaced from each other to form said slot.

4. The apparatus of claim 1 in which the hollow drum has a chamfered portion, a feed groove on said chamfered portion, said feed groove deepening from said chamfer toward said slot and intersecting said slot at the apex of a wave in said slot.

5. The generator of claim 4 in which said groove terminates adjacent and at the same depth as said slot.

6. The generator of claim 1 in which the slot includes a plurality of n waves of uniform dimension, and in which the yarn forms a secant in said slot with a chord subtending an arc of 21r/n.

7. The generator of claim 1 in which the drum is formed of a core portion and an outer portion, and in which the outer portion includes a turbine blade area.

8. The generator of claim 1 in which the slot includes a plurality of waves of different dimensions.

9. The generator of claim 8 in which the generator is associated with a winding station, the waves decrease in length and in which the sum of the lengths of the waves exceed the length of yarn to be wound on the maximum diameter of the windings to be made. 

1. Apparatus for winding textile yarn including a yarn guide, means for reciprocating said yarn guide, said yarn guide including a vibration generator mounted on said yarn guide for reciprocation therewith, said vibration generator including an assembly comprising a. a hollow drum having a circumferential slot therein, said slot having at least one wave therein, the interior of said drum being free of obstructions to a yarn entered as a secant in said slot, and b. air turbine means for rotating said hollow drum at high speed to impart low-amplitude vibrations to the yarn entered in said slot, said air turbine means including an air turbine formed at least in part by said hollow drum.
 2. The apparatus of claim 1 in which the slot includes a plurality of waves of the same dimensions.
 3. The apparatus of claim 1 in which the hollow drum includes a hub and two outer portions, the outer portions being spaced from each other to form said slot.
 4. The apparatus of claim 1 in which the hollow drum has a chamfered portion, a feed groove on said chamfered portion, said feed groove deepening from said chamfer toward said slot and intersecting said slot at the apex of a wave in said slot.
 5. The generator of claim 4 in which said groove terminates adjacent and at the same depth as said slot.
 6. The generator of claim 1 in which the slot includes a plurality of n waves of uniform dimension, and in which the yarn forms a secant in said slot with a chord subtending an arc of 2 pi /n.
 7. The generator of claim 1 in which the drum is formed of a core portion and an outer portion, and in which the outer portion includes a turbine blade area.
 8. The generator of claim 1 in which the slot includes a plurality of waves of different dimensions.
 9. The generator of claim 8 in which the generator is associated with a winding station, the waves decrease in length and in which the sum of the lengths of the waves exceed the length of yarn to be wound on the maximum diameter of the windings to be made. 